Carrier and Sons Walnuts

Background

Carriere & Sons owns and operates hundreds of acres of
walnut trees, in addition to their walnut drying facility.
They are also in partnership with Borges of California,
which is owned by Borges of Spain. Borges is the world’s
leading walnut operator and has forty-eight companies in
its group devoted to the production and marketing of oils,
dried fruits and nuts.
Walnuts are dried at a
relatively low temperature
w i t h a m a x i m u m
temperature of 110°F (43°C)
leaving the dryer. This low
temperature requirement is
ideally suited for the use of
the SolarWall®
technology.
A normal drying season
consists of two months of
drying from September 1st
to October 31st. The
walnuts are dried from 35%
moisture content to 10%
moisture content.

Solution

The SolarWall®
system was installed on the roof of a new
drying building at Carriere. The 3,200 ft2
(300 m2
) solar
system spans the entire roof area and will displace around
308 million BTU of natural gas for the two month drying
season. The system heats approximately 25,000 cfm of
air, which is then ducted into the 70,000 cfm blower.
The energy savings for two months of operation from
September 1st to October 31st, was documented to be
over 3,800 therms. (111,300 kWh) The actual dollar
savings are based on the cost of gas, which, in 2002, was
fluctuating between $0.45 and $0.93 a therm. The multifold
fluctuations in the price of natural gas since that time
has meant that Carriere has been able to keep their operating
costs stable, as well as realizing tremendous energy
savings.